Tuan Pham, Postdoctoral Fellow, Institute for Theoretical Physics (ITF), University of Amsterdam

This seminar wil cover two topics:

1 ) Cellular Adaptation to Signal Fluctuations as Learning

Cells arguably represent the most fundamental unit of life. Underlying their robust perfor mance against environmental variability, such as temporal fluctuations of chemical signals called morphogens, is a feedback between the two components of an intracellular pathway: a gene-regulatory network and its upstream signal transducers. To study such feedback, we map cellular adaptation onto a learning process of effective connections between the signal and its transducers. We show how a single cell utilises this learning mechanism to self-regulate its states, achieving robust output in the presence of variable input. We establish that such robustness emerges beyond a critical feedback strength via an abrupt change in the gene-expression collective modes as quantified by the covariance structure between intracellular components.

2) Fluctuations-Induced Segregation and Polarisation Patterns

Spatial segregation and political polarization both leave macroscopic traces in society, often in the form of clustered patterns across urban regions. Yet similar spatial patterns can arise from different microscopic mechanisms, making it difficult to infer whether observed structure is driven by residential sorting, opinion dynamics, or their interaction. Here, by deriving hydrodynamical equations from the underlying agent-based models (Schelling + voter), we establish a direct connection between micro-mechanisms and the emerging macroscale patterns.